Method and apparatus for a cutting tool

ABSTRACT

A method of making a cutting tool comprises providing a lever with a jaw having a cutting edge and a body arranged such that the cutting edge is offset from the body; providing a rotary cutting tool with an edge profile that may be complex and/or non-planar to form a complementary edge profile geometry on the cutting edge by moving the edge profile geometry of the rotary cutting tool along the length of the cutting edge.

This application claims benefit of priority under 35 U.S.C. §119(e) to the filing date of to U.S. Provisional Application No. 61/328,505, as filed on Apr. 27, 2010, which is incorporated herein by reference in its entirety.

BACKGROUND

The most common process for forming a cutting edge on a diagonal pliers is by first machining the tool when the metal is in a “soft” state using an end mill or similar cutter. One problem with this process is that it limits the geometry on the cutting edge to simple angular shapes that are limited to flat planar surfaces. The process may also lead to variations in the finished product because each cutting edge is formed by two independent machining steps determined by the depth or trajectory of each cut. Because of these variations, the process may further require hand finishing of the hardened cutting edges to bring the edges into proper final alignment. CNC machining of the cutting edges is an alternative to standard machining, but can be costly and/or slow in a production setting. CNC is also limited to only cutting the edges in the soft state of the pliers.

SUMMARY OF THE INVENTION

A method of making a cutting tool comprises providing a lever with a jaw having a cutting edge and a body arranged such that the cutting edge is offset from the body; providing a rotary cutting tool with an edge profile that may be planar and/or non-planar to form a complementary edge profile geometry on the cutting edge by moving the edge profile geometry of the rotary cutting tool along the length of the cutting edge.

Another method of making a cutting tool comprises providing a lever with a jaw having a cutting edge that may comprise complex, planar and/or non-planar shapes and a body arranged such that the cutting edge is offset from the body; providing a rotary cutting tool with a first edge profile and a second edge profile; and forming a first portion of complementary edge profile geometry on the cutting edge by moving the first edge profile of the rotary cutting tool along the length of a first side of the cutting edge and forming a second portion of complementary edge profile geometry on the cutting edge by moving the second edge profile of the rotary cutting tool along the length of a second side of the cutting edge.

The step of forming may be done when the cutting edge is in a soft state or when the cutting edge is in a hardened metal. The lever arm of the tool may be fixtured in a predetermined position. The rotary cutting tool may be fed in a straight path along the cutting edge. The rotary cutting tool may traverse the entire cutting edge. The rotary cutting tool may traverse the cutting edge without contacting the body. A plurality of levers each having a cutting edge may be fixtured such that all of the cutting edges are aligned and the rotary cutting tool is moved along a linear path along the cutting edges. The rotary cutting tool may be a grinding wheel or a form cutter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of an example cutting tool on which the methods of the invention may be used.

FIG. 2 is an end view of one lever of the tool of FIG. 1.

FIG. 3 is an end view of the other lever of the tool of FIG. 1.

FIG. 4 is a perspective view of a lever fixtured and engaged by a rotary cutting tool according to one embodiment of the method of the invention.

FIG. 5 is an end view of a lever fixtured and engaged by a rotary cutting tool according to one embodiment of the method of the invention.

FIG. 6 is a plan view of a lever showing the engagement of a rotary cutting tool with a cutting edge according to one embodiment of the method of the invention.

FIG. 7 is an end view showing a lever as designed according to one embodiment of the invention.

FIGS. 8 a and 8 b are plan views comparing the lever of FIG. 3 and the lever of FIG. 7.

FIG. 9 is a plan view showing the engagement of a rotary cutting tool with a plurality of cutting edges according to another embodiment of the method of the invention.

FIG. 10 is a perspective view of a lever fixtured and engaged by a rotary cutting tool according to yet another embodiment of the method of the invention.

FIG. 11 is an end view of a lever fixtured and engaged by a rotary cutting tool according to the embodiment of FIG. 10.

FIG. 12 is a detailed end view of the cutting edge engaged by a rotary cutting tool having a different profile.

FIG. 13 is a detailed view of FIG. 11 showing the engagement of the rotary cutting tool with the cutting edge of the lever.

FIG. 14 is a detailed view similar to FIG. 13.

FIG. 15 is an end view of a lever fixtured and engaged by a rotary cutting tool according to the embodiment of the method of the invention of FIG. 13.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A grinding or machining technique is used to create the finished geometry on the cutting edge of a tool. Grinding can be done with the pliers in either in a soft state or on hardened metal such as after induction hardening or other hardening operation. Machining is typically performed before hardening with the edge being hardened after the machining operation. The grinding operation is performed using a rotary grinding wheel that uses abrasion to remove material to form the edge. The machining operation is performed using a rotary form cutter having sharp cutting edges that cut the material to form the edge. As used herein the term “rotary cutting tool” means both a grinding wheel and a form cutter and the term “rotary cutting operation” means both an abrasive grinding operation and a form milling operation.

One lever arm of the tool is fixtured in a predetermined position before it is assembled to the other lever arm of the tool. A rotary cutting tool is fed in a straight path along the cutting edge so that the geometry of the rotary cutting tool forms the shape of the tool's cutting edge. This is advantageous because a variety of different and complex shapes may be provided to create specialized edge shapes such as parabolic, hollow ground, or compound forms that are not obtainable using known techniques and that may be used for cutting materials of differing hardness and diameter.

FIGS. 1, 2 and 3 show a diagonal cutting pliers tool. A first lever 2 is pivotably attached to a second lever 4 at pivot 6. The first lever 2 has a handle 10 at one end and a jaw 8 at the opposite end with a body 9 disposed between the handle 10 and jaw 8. The second lever 4 has a handle 12 at one end and a jaw 14 at the opposite end with a body 13 disposed between the handle 12 and jaw 14. The pivot 6 passes through apertures 20 formed in bodies 9 and 13. A first cutting edge 16 is formed on the first jaw 8 and a second cutting edge 18 is formed on the second jaw 14. The cutting edges 16 and 18 are aligned to cut an article when the levers 2 and 4 bring the jaws 8 and 14 together. Cutting tools such as the one described with reference to FIG. 1 may have a variety of jaw shapes, sizes, handle shapes, pivot arrangements or the like and may be used in a wide variety of applications. While a specific embodiment of a cutting tool is shown the method of the invention has applicability to any tool where the formation of a cutting edge using the method described herein may be advantageous.

FIGS. 2 and 3 show end views of the jaws 8 and 14 of a traditional pliers. In a traditional pliers one jaw 14 is typically arranged such that the cutting edge 18 is offset from the body 13 and handle 12 as shown in FIG. 2. The cutting plane is defined herein as a plane extending along the cutting edge and that extends through the two cutting edges of the tool (e.g. cutting edges 16 and 18) during articulation of the tool. The edge 18 is offset such that a cutting plane L-L extending through the cutting edge 18 does not interfere with the body 13 or handle 12. The other jaw 8 is typically arranged with the cutting edge 16 disposed within the width of the body 9 as shown in FIG. 3. In such an arrangement a cutting plane A-A extending through cutting edge 16 and perpendicular to the axis of rotation of the lever 4 intersects the body 9 and/or handle 10 of the lever 2.

Referring to FIG. 2 because the cutting plane L-L through the offset cutting edge 18 on jaw 14 does not interfere with the rest of lever 4, a rotary cutting tool is able to pass along edge 18 and clear the rest of the lever such that the lever does not contact or interfere with the rotary cutting tool as it passes along cutting plane L-L for the full extent of edge 18. By positioning the peripheral edge of a rotary cutting tool on the cutting edge and moving the rotary cutting tool along the cutting plane L-L and along the length of the cutting edge 18, the profile of the rotary cutting tool will create the final shape of the cutting edge 18. This method is advantageous because a rotary cutting tool can be dressed to have a wide range and variety of shapes including complex shapes that can be easily formed into edge 18. Further, a rotary cutting tool moved along the length of the cutting edge attains better precision when compared to other methods of finishing a cutting edge.

FIG. 4 shows an isometric view of lever 4 fixtured with a grinding wheel 32 passing over the cutting edge 18. FIG. 10 shows a similar isometric view except that the grinding wheel 32 is replaced by a form cutter 132. Like reference numerals are used to indentify like components in the various views. A fixture 30 fixes the lever 4 in a known position relative to the grinding wheel 32. The fixture 30 may for example have a pin 34 that closely engages aperture 20 (used to receive pivot 6 in the finished tool) and surfaces 36 that closely engage surfaces of the lever 4 to properly position the lever 4 relative to the grinding wheel 32. Typically, a clamp (not shown) clamps the lever in position such that it does not move relative to the fixture 30 during the rotary cutting operation. Any suitable fixture may be used that fixes the lever in a known position relative to the rotary cutting tool.

FIGS. 5, 11 and 12 show end views down the line of the cutting edge 18 with grinding wheel 32 and form cutter 132 engaged, with edge 18. The cutting tools are provided with profiles P, P′ and P″. The profile P of the edge of the grinding wheel 32 and the profiles P′ and P″ of the teeth 132 a of form cutter 132 can be made to have a variety of shapes, including complex shapes, non-planar shapes and shapes having a combination of planar and non-planar surfaces, where the rotary cutting tool 32, 132 creates a complimentary shape on the cutting edge 18. Profiles P and P′ show a complex cutting edge shape where all of the faces of the cutting edge are planar. Profile P″ shows a cutting edge 18 with a rounded surface at the tip. The profiles and complementary cutting edges may have a variety of complex shapes including planar and non-planar surfaces.

The rotary cutting tool 32, 132 is moved along the length of edge 18 such that the rotary cutting tool 32, 132 forms the shape of the edge 18 but does not interfere with the rest of the tool. The rotary cutting tool 32, 132 is arranged such that the rotational axis a-a of the rotary cutting tool 32, 132 is normal to the cutting plane of the edge. FIG. 6 shows a top view of the cutting path CP of the rotary cutting tool 32, 132 relative to the lever arm. As can be seen from the figures because cutting plane L-L is offset from the rest of lever arm 4, the rotary cutting tool 32, 132 is able to traverse the entire length of the cutting edge 18 in a straight line without contacting any other part of the lever.

This method can be used on any cutting tool where the rotary cutting tool 32, 132 is able to traverse the cutting edge without interfering with or contacting the remainder of the tool. Referring to FIGS. 2, 3, 11 and 12 in a traditional tool the method of the invention may be used with jaw 14, however, it cannot be used with jaw 8 because the cutting plane A-A through cutting edge 16 extends into the body 9 of lever 2 as illustrated in FIG. 3. If the rotary cutting tool is passed over edge 16 along plane A-A it would strike body 9. Thus, in a traditional pliers the manufacturing process of the invention may be used to create one cutting edge while the other cutting edge may be made with existing technology.

To use the grinding method of the invention on both jaws of the tool, both jaws may be designed with the cutting edge being offset outside of the width of the body of the lever. FIG. 7 shows an end view of a jaw and lever having the cutting edge 28 offset from the body of the lever to allow clearance for the rotary cutting tool along cutting plane P-P. The lever of FIG. 7 is used in place of the lever 2 and jaw 8 (FIG. 3) in one embodiment of the tool. FIGS. 8 a and 8 b are top views showing a traditional lever (FIG. 8 a) and the offset edge lever of the invention (FIG. 8 b). In the offset edge design of FIG. 8 b the lever 4 comprises a handle 10 connected to jaw 24 by body 9. Jaw 24 comprises a cutting edge 28 that is positioned such that a cutting plane P-P that extends through edge 28 is offset from the body 9 such that a rotary cutting tool 32, 132 is able to traverse the entire length of the cutting edge 28 without contacting any other part of the lever. The use of offset edges on both jaws of the tool creates a visual difference in the look of the tool over traditional jaws and may result in a cutting edge alignment with a slightly different angled face than a traditional tool, but the overall operation of the pliers is the same as traditional pliers.

Another benefit of using rotary cutting tool 32, 132 as described herein is that multiple levers can be fixtured in alignment such that one rotary cutting tool 32, 132 can follow a linear path along the aligned cutting edges of multiple tools. Referring to FIG. 9, three levers 2 are shown as mounted in fixtures (not shown) with the cutting edges 18 aligned on a common line D. A single rotary cutting tool 32, 132 follows a linear path along line D to form the cutting edges 18 on a plurality of tools in one operation. This method can be used to increase production rates and lower manufacturing costs for high volume production.

Referring to FIGS. 13, 14 and 15 an alternate embodiment of the method of forming a cutting edge is shown. The method is illustrated where the rotary cutting tool is a form cutter 132 although the method may also use a grinding wheel. Unlike the rotary cutting tool previously described, the profile P″ formed on the cutting tips of the rotary cutting tool is formed with two half profiles rather than the full geometry profile as previously described. Referring to FIG. 14 cutting profile P″ has a first half profile P1 formed on one side of the rotary cutting tool and a second half profile P2 formed on the other side of the rotary cutting tool. The profiles P1 and P2 are arranged such that one profile P1 is brought into contact with one side of the cutting edge 18 to form half of the cutting edge in a first pass of the rotary cutting tool and the other profile P2 is brought into contact with the other side of the cutting edge 18 to form the other half of the cutting edge in a second pass of the rotary cutting tool.

To form the cutting edge 18 a rotary cutting tool as described above is provided. A first cutting profile P1 is disposed along one side of the rotary cutting tool and the rotary cutting tool is aligned such that the rotary cutting tool is passed over the cutting edge 18 in a linear path, as previously described, with the first cutting profile P1 forming one half of the cutting edge as shown in FIGS. 13 and 14. The rotary cutting tool is then indexed transversely to the cutting edge the approximate width of the cutting edge such that the second cutting profile P2 is disposed along the other side of the cutting edge 18. The rotary cutting tool is aligned such that the rotary cutting tool is passed over the cutting edge 18 in a linear path, as previously described, with the second cutting profile P2 forming the second half of the cutting edge as shown in FIG. 15. While the invention has been described with each cutting profile P1, P2 forming half of the cutting edge, each profile may form more or less than one-half of the cutting edge provided the plural cutting profiles form a complete cutting edge.

While embodiments of the invention are disclosed herein, various changes and modifications can be made without departing from the spirit and scope of the invention as set forth in the claims. One of ordinary skill in the art will recognize that the invention has other applications in other environments. Many embodiments are possible. The following claims are in no way intended to limit the scope of the invention to the specific embodiments described above. 

1. A method of making a cutting tool comprising: providing a lever comprising a jaw having a cutting edge and a body arranged such that the cutting edge is offset from the body; providing a rotary cutting tool with an edge profile geometry; forming a complementary edge profile geometry on the cutting edge by moving the edge profile geometry of the rotary cutting tool along the length of the cutting edge.
 2. The method of claim 1 wherein the step of forming is done when the cutting edge is in a soft state.
 3. The method of claim 1 wherein the step of forming is done when the cutting edge is in a hardened metal.
 4. The method of claim 1 wherein the lever arm of the tool is fixtured in a predetermined position.
 5. The method of claim 1 where the rotary cutting tool is fed in a straight path along the cutting edge.
 6. The method of claim 1 where the rotary cutting tool traverses the entire cutting edge.
 7. The method of claim 1 where the rotary cutting tool traverses the cutting edge without contacting the body.
 8. The method of claim 1 further comprising providing a plurality of levers each having a cutting edge, fixturing the plurality of levers such that each cutting edge of the plurality of levers are aligned, moving the rotary cutting tool along a linear path along the cutting edges.
 9. The method of claim 1 wherein the rotary cutting tool is a grinding wheel.
 10. The method of claim 1 wherein the rotary cutting tool is a form cutter.
 12. A method of making a cutting tool comprising: providing a lever comprising a jaw having a cutting edge and a body arranged such that the cutting edge is offset from the body; providing a rotary cutting tool with a first edge profile and a second edge profile; forming a first portion of complementary edge profile geometry on the cutting edge by moving the first edge profile of the rotary cutting tool along the length of a first side of the cutting edge and forming a second portion of complementary edge profile geometry on the cutting edge by moving the second edge profile of the rotary cutting tool along the length of a second side of the cutting edge.
 13. The method of claim 12 wherein the step of forming is done when the cutting edge is in a soft state.
 14. The method of claim 12 wherein the step of forming is done when the cutting edge is in a hardened metal.
 15. The method of claim 12 wherein the lever arm of the tool is fixtured in a predetermined position.
 16. The method of claim 12 where the rotary cutting tool is fed in a straight path along the cutting edge.
 17. The method of claim 12 where the rotary cutting tool traverses the entire cutting edge.
 18. The method of claim 12 where the rotary cutting tool traverses the cutting edge without contacting the body.
 19. The method of claim 12 further comprising providing a plurality of levers each having a cutting edge, fixturing the plurality of levers such that each cutting edge of the plurality of levers are aligned, moving the rotary cutting tool along a linear path along the cutting edges.
 20. The method of claim 1 wherein the rotary cutting tool is a grinding wheel or a form cutter. 